Posture seat cushion



FIG. 1 is a front top perspective view of the posture seat cushion of the invention.

FIG. 2 is a top view of the posture seat cushion of FIG. 1.

FIG. 3 is a front view of the posture seat cushion of FIG. 1, wherein the rear view and side views are identical; and,

FIG. 4 is a bottom view of the handle plate of FIG. 1.

The features inside the dashed lines boundary form no part of the design. 

CLAIM The ornamental design for posture seat cushion, as shown and described. 